(1) A number of methods have been proposed for producing a propylene oxide-based polymer having at least one reactive, functional silicon group in the molecule, as described later, and some of them are already produced industrially. An organic polymer with polyoxy propylene forming as the main chain and functional methoxy silyl group bound to the terminal, e.g., the one produced and sold by Kaneka Corporation (MS Polymer™), may be insufficient in elongation of the cured product and have residual tackiness on the surface, depending on its purposes, due to the effects of the composition and service conditions.
Japanese Patent Laid-Open Publication No.34066/1986 discloses a composition of improved tensile characteristics, characterized in that it comprises a propylene oxide-based polymer having at least one reactive, functional silicon group in the molecule, a compound having one silanol group in the molecule, and/or a compound which can react with water to form a compound having one silanol group in the molecule. Japanese Patent Laid-Open Publication No.34067/1986 discloses a curable, elastic composition, characterized in that it comprises an organic vinyl-based polymer having at least one reactive, functional silicon group in the molecule, a compound having one silanol group in the molecule, and/or a compound which can react with water to form a compound having one silanol group in the molecule.
Therefore, there are demands for a curable elastic composition (curable rubber composition) improved in elongation of the cured product and in residual tackiness, and, at the same time, high in curing speed and capable of giving the cured product of high resistance to weather.
(2) It is known that a saturated hydrocarbon-based polymer (which is essentially free of an unsaturated C—C bond, except aromatic ring) having at least one reactive silicon group in the molecule shows interesting nature that it is crosslinked even at room temperature by the hydrolysis of the reactive silicon group with moisture or the like, followed by formation of the siloxane bond to form a rubber-like cured product, wherein the “reactive silicon group” means the silicon-containing group which has a hydrolyzable group bound to the silicon atom and can form the siloxane bond.
Such a saturated hydrocarbon-based polymer has the main chain composed of a saturated hydrocarbon, which is resistant to heat-or light-caused deterioration, can give a cured product excellent in resistance to heat and weather, and gas-barrier property. The saturated hydrocarbon-based polymer, therefore, can find uses, e.g., sealant for laminated glass and elastic sealant for buildings.
A silanol condensing catalyst can be used for crosslinking/curing a polymer having a reactive silicon group. Use of this type of catalyst can reduce curing time. In particular, a sealant for laminated glass, a product which must be delivered in a very short procurement period, is required to be cured very quickly. As such, a strong, silanol-condensing catalyst is required for the above purposes.
Japanese Patent Laid-Open Publication No. 41360/1996 discloses a curable composition which uses a compound represented by the general formula Q2Sn(OZ)2 or [Q2Sn(OZ)]2O (wherein, Q is a monovalent hydrocarbon group of 1 to 20 carbon atoms; and Z is an organic group having a functional group which can form a coordinate bond with Sn within its structure or a monovalent hydrocarbon group of 1 to 20 carbon atoms) serving as the silanol condensing catalyst to accelerate curing of a saturated hydrocarbon-based polymer having a reactive silicon group. These curing catalysts tend to accelerate curing of the saturated hydrocarbon-based polymer faster than a divalent tin-based curing catalyst (e.g., tin octylate) or tin carboxylate catalyst (e.g., dibutyl tin dilaurate). However, curing time is required to be still shorter for a sealant for laminated glass, a product which must be delivered in a very short procurement period.
Several additives have been proposed to accelerate the silanol condensation for a saturated hydrocarbon-based polymer having a reactive silicon group. For example, Japanese Patent Laid-Open Publication No. 97562/1990 discloses a curable composition which uses “a polyhydroxymonosilane having two or more silicon-bonded hydroxyl groups in the molecule.” Japanese Patent Laid-Open Publication No. 196842/1990 discloses a curable composition which uses “a silicon compound, other than polysiloxane, having two or more silicon-bonded hydroxyl groups and two or more silicon atoms in the molecule.” Incorporation of one of these silanol compounds does improve curability, which, however, is still insufficient, and a more effective additive is in demand.
A sealant for laminated glass is required to have non-primer adhesion, i.e., to be fast adhesive to a variety of objects in the absence of a primer. More recently, the above property has been required not only for sealant for laminated glass but also for sealant for other purposes, e.g., by elastic sealant for buildings, to improve application efficiency by dispensing with a primer. However, the sealant which uses the above-described saturated hydrocarbon-based polymer containing a reactive silicon group is insufficient in adhesion in the absence of a primer.
Japanese Patent Laid-Open Publication No. 116832/1999 describes that the inventors have found, after having extensively studied to solve the above problems, that the composition can have improved curing speed and adhesion without causing any problem, e.g., deteriorated properties of the cured product, when incorporated with a specific compound, reaching the invention.
The invention disclosed by the above publication relates to a curable composition of improved curing speed and adhesion, characterized in that it comprises (A) a saturated hydrocarbon-based polymer having at least one reactive silicon group, (B) a tetravalent tin compound, and (C) a silicon compound represented by the general formula R1aSi(OR2)4-a (wherein, R1 and R2 are each a hydrocarbon group of 1 to 20 carbon atoms, which may be substituted or not substituted; and “a” is an integer of 0 to 3), in particular, comprising (A) 100 parts by weight of a saturated hydrocarbon-based polymer having at least one reactive silicon group in the molecule and molecular weight of 500 to 50,000, (B) 0.1 to 20 parts by weight of a tetravalent tin alcoholate, and/or (C) 0.01 to 20 parts by weight of a silicon compound represented by the general formula R1aSi(OR2)4-a (wherein, R1 is an aryl group of 1 to 20 carbon atoms; R2 is a hydrocarbon group of 1 to 20 carbon atoms, which may be substituted or not substituted; and “a” is an integer of 0 to 3).
The inventors of the present invention have double-checked the curable composition described in the above publication, to confirm that its curing speed is admittedly improved but still insufficient.
Therefore, there are demands for a curable rubber composition still higher in curing speed, and more excellent in adhesion to a variety of objects and resistance to weather.
(3) One example of the reactive silicon group is represented by the formula —Si(OCH3)3 and hydrolyzable with moisture in air into —Si(OH)3, which reacts with another reactive silicon group through silanol condensation to form a siloxane bond (Si—O—Si). Therefore, the polymer containing a reactive silicon compound can be crosslinked/cured in the presence of moisture even at room temperature. Of these polymers, an oxyalkylene polymer with, e.g., polyoxypropylene in the main chain skeleton, has been widely used as sealant for buildings and other industrial purposes, because of its characteristics, e.g., liquid at room temperature and curable into a rubber elastomer. However, when it is used to fill a joint (i.e., gap between the construction material, e.g., wall material) or the like, it leaves residual tackiness on the cured product surface, even after it is cured, deteriorating the outer appearances resulting from contamination of the surface with dust or the like. A paint may be applied to the cured product surface. In this case, the paint is not always sufficiently adhesive to the sealant surface, in particular when a solvent-based paint is used.
Japanese Patent Laid-Open Publication No. 302213/1997 discloses a curable composition comprising (a) an oxyalkylene polymer containing at least one reactive silicon group in the molecule, and (b) a silicon compound containing at least one amino group and at least one trialkyl siloxy group in the molecule. It is claimed to leave residual tackiness to only a limited extent, after it is cured, and to be highly adhesive to a paint.
Nevertheless, improvements of these characteristics are still insufficient, and more improvements in curing speed and resistance of the cured product to weather are demanded.
Therefore, there are demands for a curable composition high in curing speed, leaving little residual tackiness on the cured product surface, after it is cured, highly resistant to weather, showing high adhesion between a paint and sealant surface, when the former is applied, and useful for sealant, primer or the like.
(4) RTV (room temperature vulcanizable) silicone rubber is well known as a polymer curable even at low temperature (room temperature) to form a rubber-like material, and has been used for sealants for buildings and a variety of formed materials. However, RTV silicone rubber, having polysiloxane in the main chain, is expensive and insufficient in some properties.
Therefore, a rubber-based organic polymer curable at room temperature like RTV silicone rubber is proposed by, e.g., Japanese Patent Laid-Open Publication No. 156599/1975. It has a rubber-based organic polymer instead of polysiloxane in the main chain.
The polymer has a functional, reactive silicon group which is curable by forming the siloxane bond and is curable even at room temperature, like RTV silicone rubber, to form a rubber-like material by the following reaction. It is cheaper than polysiloxane, and has characteristics which polysiloxane lacks.
wherein, X′ is a hydrolyzable group.
Rubber is generally required to have tensile characteristics of low modulus and high elongation, and so is a rubber-based organic polymer having the reactive silicon group.
Japanese Patent Laid-Open Publication Nos. 34066/1986 and 34067/1986 propose incorporation of monovalent silanol compound or derivative thereof as the method to improve modulus and elongation of a cured rubber-based organic polymer having a reactive silicon group.
The compound disclosed by each of the above publications may not always improve modulus and elongation sufficiently, and may leave problems, even when modulus and elongation are improved, e.g., insufficient curing of the cured product to leave tackiness on the surface, insufficient properties for formed materials or sealants, and poor storage stability of the composition. In other words, few conventional curable compositions containing a rubber-based organic polymer having a reactive silicon group satisfy all of the requirements of excellent modulus and elongation of the cured product, free of residual tackiness on the cured product surface, and excellent storage stability of the composition.
Japanese Patent Publication No. 96648/1995 discloses a combination of rubber-based organic polymer and organosiloxane compound, the former having a functional, reactive silicon group crosslinking-cured by the siloxane bond. However, it is still insufficient in curing speed and resistance to weather, among others.
Therefore, there are demands for a curable composition containing a rubber-based organic polymer having a reactive, functional silicon group, which is rapidly cured with moisture, excellent in tensile-related properties, capable of giving a rubber-like elastomer free of residual tackiness on the surface, and improved in resistance to weather and storage stability.
(5) It is already known that a vinyl-based resin containing a hydrolyzable silyl group is hydrolyzed at normal temperature with moisture in air to form a resin of dense network structures, excellent in, e.g., gloss, resistance to weather, discoloration and solvent, hardness, and adhesion to inorganic base materials.
A vinyl-based resin containing a hydrolyzable silyl group can find wide uses, e.g., paint, adhesive, coating material, sealant and binder, because of its favorable characteristics described above.
However, a vinyl-based resin containing a hydrolyzable silyl group is not always satisfactory in adhesion to organic base materials. For example, a paint for repairing automobiles is required to be adhesive to coating films of various conventional paints, in particular to melamine acrylic and melamine alkyd paints.
One of the known methods to improve adhesion to melamine acrylic and melamine alkyd paints is incorporation of an amine-based silane coupling agent or modification thereof, which, however, may cause problems, e.g., reduced storage stability of the vinyl-based copolymer containing a hydrolyzable silyl group and its tendency to coloration.
Japanese Patent Laid-Open Publication No. 75567/1989 discloses a resin composition curable at room temperature, comprising (A) 100 parts by weight of a vinyl-based polymer containing a silyl group, with the main chain essentially composed of a vinyl-based polymer chain and at least one silicon atom bonded to a hydrolyzable group at the terminal or in the side chain in the molecule, (B) 0.1 to 100 parts by weight of a specific silane compound, and (C) 0 to 20 parts by weight of a curing catalyst. It describes that vinyl-based copolymer containing a hydrolyzable Silyl group can have greatly improved adhesion to melamine alkyd paint or melamine acrylic paint, when incorporated with a specific silane compound, and that the resin composition curable at room temperature is found to have improved properties, e.g., hardness, and resistance to solvent and contamination of the cured coating film.
However, the composition is not always satisfactory in resistance to weather. The publication is completely silent on ethylene/α-olefin/non-conjugated polyene random copolymer rubber.
Therefore, there are demands for a rubber composition curable at room temperature, high in curing speed, excellent in resistance to weather, and capable of giving its highly adhesive cured product.
(6) A compound having a reactive silyl group is used for various purposes, e.g., paint, coating material, silane coupling agent, adhesive for rubber and sealant, for reactivity of its silyl group. In particular, the compound having a condensed silyl group curable at room temperature, having a reactive group, e.g., hydroxy, acetoxy, oxime or alkoxy group, has found wide applications.
The compound having a condensed silyl group curable at room temperature is hydrolyzed normally in the presence of a curing catalyst, although the hydrolysis proceeds with moisture in air in the absence of the catalyst. The well-known curing catalysts include organotin compounds, e.g., dibutyl tin dilaurate and dibutyl tin dimaleate. However, they are slow in curing speed, showing little curing acceleration effect under heating at low temperature of around 60 to 80° C., and still low curing speed even at baking temperature of 120 to 300° C. Therefore, there are demands for a catalyst higher in curing speed than the conventional organotin compound. There are problems to be solved when the catalyst is used for repairing automobiles and coating bridges, which need a quick-drying paint, and for the purposes which need a simple coating system, e.g., production lines for new vehicles, curtain walls and precoated metals.
Japanese Patent Laid-Open Publication No. 660/1990 discloses a curable composition containing, as the effective ingredients;    (A) at least one type of compound containing a silyl group selected from the group consisting of polyester having at least one type of specific silyl group, vinyl-based copolymer with acrylic or methacrylic acid, diallyl phthalate-based compound and diallyl phthalate-based copolymer,    (B) an amine compound selected from the group consisting of aliphatic amine, alicyclic amine, modified cycloaliphatic polyamine and ethanol amine,    (C) a silane coupling agent, represented by the general formula Y3—Si-Z, wherein Y is an alkoxyl group; and Z is an alkyl group containing a functional group selected from the group consisting of an amino group which may be substituted with an aminoalkyl group or mercapto group), and    (D) a lacquer-based paint, an acryl lacquer-based paint, an acrylic resin-based paint, a thermosetting acrylic-based paint, an alkyd paint, a melamine paint, an epoxy-based paint, or organopolysiloxane.
The publication also describes that a silyl-containing compound having a hydrolyzable group can be cured faster, in particular under heating, when incorporated with a catalyst quantity of a specific amine compound and silane coupling agent, and further with a lacquer-based, acryl lacquer-based, acrylic resin-based, thermosetting acrylic-based paint, alkyd paint, melamine paint, epoxy-based paint, or organopolysiloxane, without causing any adverse effect on properties of the cured product of lacquer-based, acryl lacquer-based, acrylic resin-based, thermosetting acrylic-based paint, alkyd paint, melamine paint, epoxy-based paint, or organopolysiloxane.
However, the inventors of the present invention have double-checked the composition to confirm that it is still insufficient in curing speed and unsatisfactory in resistance to weather. It also describes a silyl-containing compound having a hydrolyzable group, but is completely silent on ethylene/α-olefin/non-conjugated polyene random copolymer rubber.
Therefore, there are demands for a curable rubber composition, easily cured with moisture in air at room temperature or under heating, and at high speed, and excellent in resistance to weather of the cured product.
(7) Japanese Patent Laid-Open Publication No. 73998/1977, for example, discloses an oxyalkylene-based polymer having a silicon-containing group with hydroxyl and/or a hydrolyzable group bonded to the silicon atom, and crosslinkable by forming the siloxane bond (such a silicon-containing group is here in after referred to as reactive silicon group). It is typically represented by the following general formula:X″3SiOxypropylene polymerSiX″3wherein, X″ is a hydrolyzable group, e.g., methoxy group.
An oxyalkylene-based polymer having a reactive silicon group is cured at room temperature after forming the siloxane bond (Si—O—Si) between the polymer molecules by the action of moisture in air, as is the case with a silicon rubber curable at room temperature, to form a rubber-like cured product. The cured product has been used for, e.g., sealant and adhesive, because of its excellent properties, e.g., elongation, strength and adhesion.
The rubber-like cured product, when to be used for sealant or the like, is required to have various properties of which tensile-related characteristics and adhesion to an object are more important. The tensile-related characteristics include modulus, elongation and breaking strength, and low modulus and high elongation as the characteristics of rubber are frequently required. Adhesion includes adhesive strength to an object and its resistance to weather, and high adhesive strength and high resistance to weather are required. In particular, it is frequently used as a sealant for buildings for transparent materials, e.g., glass, and is required to have high resistance of adhesive strength to weather, especially while it is irradiated with sunray.
Japanese Patent Laid-Open Publication No. 34066/1986 proposes a composition comprising an oxyalkylene-based polymer having a reactive silicon group and a compound having a silanol group in the molecule and/or a compound having a hydrolyzable silicon group in its molecule reacting with moisture to form a compound with a silanol group in the molecule (hereinafter referred to as monovalent silanol-based compound), as the one which gives a low-modulus cured product.
Japanese Patent Laid-Open Publication No. 182350/1982 discloses use of a compound having amino group and a silicon atom with a hydrolyzable group, e.g., γ-aminopropyltrimethoxysilane (H2NCH2CH2CH2Si(OCH3)3) or γ-aminopropylmethyldimethoxysilane (H2NCH2CH2CH2Si(CH3) (OCH3)2) bonded to the silicon atom, to improve adhesion of the cured product of oxyalkylene-based polymer having a reactive silicon group.
However, a composition containing a compound having a silicon atom to which 3 hydrolyzable groups are bonded, e.g., γ-aminopropyltrimethoxysilane, has a disadvantage of deteriorated effect of the monovalent silanol-based compound, due to increased modulus of its cured product. On the other hand, a composition containing a compound having a silicon atom to which 2 hydrolyzable groups are bonded, e.g., γ-aminopropylmethyldimethoxysilane, has a disadvantage of insufficient resistance of its adhesive strength to weather, although its cured product scarcely has an increased modulus.
Japanese Patent Laid-Open Publication No. 117955/1990 proposes a composition comprising an oxyalkylene-based polymer having a reactive silicon group and monovalent silanol-based compound, incorporated with a compound having amino group and a silicon atom to which 2 hydrolyzable groups are bonded, and a small quantity of a compound having amino group and a silicon atom to which 3 hydrolyzable groups are bonded, as the curable composition of improved modulus-related properties, adhesive strength to an object and resistance of adhesive strength to weather. However, the curable product of the above composition is still insufficient in resistance to weather, leaving room for further improvement.
Therefore, there are demands for a curable composition high in curing speed, giving a weather-resistant cured product, and suitable for adhesive, sealant or the like.
(8) Japanese Patent Laid-Open Publication No. 73998/1977, for example, discloses an oxyalkylene-based polymer having a silicon-containing group with hydroxyl and/or a hydrolyzable group bonded to the silicon atom, and crosslinkable by forming the siloxane bond (such a silicon-containing group is hereinafter referred to as reactive silicon group). It is typically represented by the following general formula:X″3SiOxypropylene polymerSiX″3wherein, X″ is a hydrolyzable group, e.g., methoxy group.
An oxyalkylene-based polymer having a reactive silicon group is cured at room temperature after forming the siloxane bond (Si—O—Si) between the polymer molecules by the action of moisture in air, as is the case with a silicon rubber curable at room temperature, to form a rubber-like cured product. The cured product has been used for, e.g, sealant and adhesive, because of its excellent properties, e.g., elongation, strength and adhesion.
In general, the polymer is frequently used as a composition incorporated with a filler for, e.g., cost reduction. However, incorporation of a filler substantially increases the viscosity of the composition, and use of a plasticizer is technically essential to sufficiently reduce the viscosity to make the composition processable by the common method.
In general, use of a filler or plasticizer causes various problems, of which deteriorated storage stability, especially that leading to decreased curing speed of the stored composition, is more serious.
Therefore, there are demands for a curable composition high in curing speed and storage stability (especially quickly cured when it is used, even after being stored for extended periods), and giving a weather-resistant cured product.
(9) A vinyl-based resin containing silyl group is characterized in that it is curable at room temperature with moisture, in particular that in air, which opens up wide applicable areas for the composition. However, its disadvantages of short pot life and insufficient resistance to weather have sometimes limited its applications.
Japanese Patent Publication No. 47747/1988 proposes an invention relating to a vinyl-based resin composition. The vinyl-based resin (A) containing silyl group for the composition has at least one silyl group represented by
(wherein, R1 and R2 are each hydrogen or monovalent hydrocarbon group selected from the group consisting of alkyl, aryl and aralkyl group of 1 to 10 carbon atoms; X is a halogen or a group selected from the group consisting of alkoxy, acyloxy, aminoxy, phenoxy, thioalkoxy and amino group, at least one being alkoxyl or phenoxy group; and “a” is an integer of 0 to 2) in the molecule, and also has a molecular weight of 1,000 to 20,000.
The publication describes that the curable composition is stable, and comprising (A) the above vinyl-based resin, (B) an alcohol and/or alkyl orthoformate, and (C) an alkoxysilane compound. It also describes that the invention relates to a composition containing a compound which contains a silyl group at the terminal or in the side chain. It is curable at room temperature with moisture, in particular that in air, which is characteristic of a vinyl-based resin containing a silyl group, and, at the same time, is characterized by stability of long pot life. As such, it is very suitable as a resin for solventless or high solid content type paint, which has been attracting much attention as the non-polluting, energy-saving type paint. In particular, the resin of the invention, the publication describes, has a lower molecular weight than the conventional vinyl-based resin, which brings about a great advantage that it is applicable more easily to a non-polluting or high solid content type paint. The vinyl-based resin containing a silyl group for the composition of the invention can be easily produced by, e.g., reacting a vinyl-based resin having a C—C double bond with a hydrosilane compound in the presence of a catalyst of Group VIII transition metal.
However, the inventors of the present invention have double-checked the curable composition to confirm that it is still insufficient in curability at room temperature and resistance to weather, although it admittedly has the above-described characteristics.
Therefore, there are demands for a curable rubber composition high in storage stability and curing speed, and giving a highly weather-resistant cured product.
(10) A silicon-containing group having a hydrolyzable group bonded to the silicon atom and crosslinkable by forming a siloxane bond (such a group is hereinafter referred to as reactive silicon group) may be represented by —Si (OCH3)3, which is a well-known functional group.
This functional group is hydrolyzed with moisture, e.g., that in air, into —Si(OH)3 or the like, which reacts with another reactive silicon group to form a siloxane bond (Si—O—Si) by silanol condensation.(CH3O)3Si˜˜˜˜˜˜˜˜Si(OCH3)3→[(HO)3Si˜˜˜˜˜˜˜˜Si(OH)3]→(˜˜˜˜SiO)3Si˜˜˜˜˜˜˜˜Si(OSi˜˜˜˜)3
Therefore, a polymer having a reactive silicon group can be crosslinked/cured even at room temperature in the presence of moisture. Of these polymers, the one with a rubber-based main chain skeleton has characteristics of being highly viscous liquid at room temperature and being cured into a rubber elastomer, and is widely used as sealant for buildings and other industrial purposes. Such sealant is applied to a gap (joint) of a construction material, to fill up and keep it water-and air-tight, after it is cured.
Of these rubber-based polymers, a saturated hydrocarbon-based polymer, e.g., polyisobutylene, can yield a cured product excellent in resistance to weather and heat, and gas-barrier property. High gas-barrier property means high moisture-blocking property, which is a disadvantage for a polymer to be cured with moisture in air, because it needs a fairly long time, a week or more, to be thoroughly cured inside, although cured soon on the surface. Japanese Patent Laid-Open Publication No. 185565/1990 proposes a composition which is dispersed with a hydrate of metallic salt to be quickly cured at room temperature to deep inside.
The polymer having a reactive silicon group is frequently used after being incorporated with a silanol condensing catalyst (curing catalyst), filler, plasticizer or the like to form the curable composition. The curable compositions may fall into two general categories, one-liquid and two-liquid types. The one-liquid type curable composition is a liquid containing all of the above-described additives. It is convenient in that it needs no mixing procedure before use, but must be kept completely dehydrated to prevent curing before use. On the other hand, two-liquid type curable composition is less convenient in that it needs the mixing procedure before use, but not necessarily kept dehydrated as completely as the one-liquid type, because the polymer having a reactive silicon group will not be cured easily in the absence of the silanol condensing catalyst, even when moisture is present to some extent.
A hydrate of metallic salt, described above, cannot be used as the moisture source for curing the polymer which is used to produce a one-liquid type curable composition, because curing of the polymer will start as soon as it is mixed with a silanol condensing catalyst and the hydrate.
Titanium and tin compounds are frequently used as silanol condensing catalysts. Many of them are decomposed in the presence of moisture, and it is considered that the silanol condensing catalysts are decomposed by a hydrate of metallic salt. Therefore, a hydrate of metallic salt, when used as the moisture source, is added to a curable composition immediately before the composition is used (cured), or to the major ingredient of a two-liquid type composition, i.e., that containing the polymer component.
However, it is inconvenient to add only the hydrate of metallic salt immediately before the composition is used (cured). Moreover, incorporation of the hydrate of metallic salt in the major ingredient may cause another problem i.e., increased viscosity of the major ingredient as a result of curing of the polymer having a reactive silicon group, although to a limited extent.
A sealant is frequently incorporated with a silane coupling agent as the tackifier. However, a silane coupling agent is liable to react with moisture, and cannot be added as the additive neither to the major ingredient nor hardening agent. For example, a silane coupling agent such as γ-isocyanate propyltrimethoxysilane (ONCCH2CH2CH2Si(OCH3)3) reacts with a hydrate of metallic salt when added to the major ingredient, and is decomposed by the silanol condensing catalyst when added to the hardening agent, with the result that it will no longer work as the silane coupling agent for, e.g., increasing tackiness.
Japanese Patent Laid-Open Publication No. 182992/1998 discloses a curable composition. The object of the invention is to provide a curable composition of a saturated hydrocarbon-based polymer and a hydrate of metallic salt as the moisture source, the former having a silicon-containing group, e.g., a hydrolyzable group of silicon to which moisture-curable polyisobutylene is bonded, and crosslinkable by forming the siloxane bond, as the composition showing no increase in viscosity while it is being stored. Another object of the invention is to provide a curable composition which can incorporate a compound, e.g., that, like a silane coupling agent, having a reactive silicon group readily reactive with moisture. The invention provides a two-liquid or multi-liquid type curable composition with hydrate of metallic salt incorporated in a hardening agent containing a silanol condensing catalyst. In short, the invention provides a two-liquid and multi-liquid type curable compositions composed of at least two types of liquids of (A) a major ingredient of saturated hydrocarbon-based polymer having a hydrolyzable group bonded to silicon, and a silicon-containing group crosslinkable by forming the siloxane bond, and (B) a hardening agent containing a silanol condensing catalyst and hydrate of metallic salt.
However, there is still room for improvement in the isobutylene-based polymer as the saturated hydrocarbon-based polymer of the invention, because of its insufficient curing speed and resistance to weather.
The publication is silent on a multi-liquid type curable rubber composition, composed of at least two types of liquids, containing a silyl-containing ethylene/α-olefin/non-conjugated polyene random copolymer rubber which has a structural unit derived from a norbornene compound as the non-conjugated polyene with a specific terminal vinyl group, and contains a specific hydrolyzable silyl group in the molecule.
Therefore, there are demands for a curable rubber composition which incorporates a hydrate of metallic salt as the moisture source, showing no increase in its viscosity while being stored, high in curing speed and resistance to weather, and can incorporate a compound having a reactive silicon group readily reactive with moisture, e.g., a silane coupling agent.
(11) Japanese Patent Laid-Open Publication No. 6041/1988 discloses an isobutylene-based polymer having, at the molecular terminal, a silicon-containing group with hydroxyl or a hydrolyzable group bonded to the silicon atom and crosslinkable by forming the siloxane bond (such a group is hereinafter referred to as reactive silicon group). It is curable even at normal temperature with moisture into a rubber-like cured product excellent in properties, e.g., resistance to heat, water and weather.
However, the cured product necessarily has a long molecular chain to have good rubber elasticity, which invariably increases its viscosity and makes it difficult to handle. This disadvantage may limit its use, due to difficulty in application. Decreasing the viscosity of the polymer to avoid the above problems will invariably cause insufficient elongation-related properties of the polymer. The high moisture-barrier property of the cured isobutylene-based polymer may deteriorate its curability, because of insufficient supply of moisture necessary for curing.
Japanese Patent Laid-Open Publication No. 252670/1989 proposes, in order to solve the above problems, a curable resin composition comprising a saturated hydrocarbon-based polymer having at least one silicon-containing group with hydroxyl or a hydrolyzable group bonded to the silicon atom and crosslinkable by forming the siloxane bond, and also an organosilicon polymer. The composition, however, cannot always solve the above problems sufficiently, and is insufficient in resistance to weather and curing speed of the cured product.
Therefore, there are demands for a composition low in viscosity, good in workability, sufficient in curing speed, excellent in, e.g., resistance to weather, heat and water, and capable of giving a rubber-like cured product high in strength and elongation (low modulus of elasticity).
(12) The main chain skeleton of an ethylene/α-olefin/non-conjugated polyene random copolymer rubber is composed of a structural unit derived from ethylene and that from α-olefin, and a small quantity of copolymerized non-conjugated polyene-based monomer as the third component to introduce the unsaturated C—C bond necessary for crosslinking. As a result, it is used as a vulcanizable elastomer which can give the vulcanized product much higher in resistance to heat and weather than a diene-based elastomer, e.g., natural rubber, polyisoprene or polybutadiene. However, resistance to weather of the vulcanized product is still damaged by the unsaturated C—C bond for vulcanization, although it has a significantly smaller quantity of the unsaturated C—C bond than a diene-based elastomer.
Viewed from vulcanization speed, it is slow due to insufficient quantity of the unsaturated C—C bond, limiting speed of the production line for vulcanization. This should be one of the causes for a cost increase.
Therefore, there are demands for a rubber composition high in vulcanization speed, improved in resistance to weather and excellent in mechanical strength, while keeping the various favorable characteristics of an ethylene/α-olefin/non-conjugated polyene random copolymer rubber, e.g., excellent resistance to heat and chemicals of the vulcanized product.
(13) A polymer having a hydrolyzable silyl group (a silicon-containing group having hydroxyl or a hydrolyzable group bonded to the silicon atom, and capable of forming the siloxane bond) is crosslinked/cured in the presence of moisture, and hence can be used as a curable composition. Of these polymers, the one with polyether serving as the main chain skeleton is generally known as a modified silicone, and has been widely used for sealant or the like.
A mixture of a polymer having a hydrolyzable silyl group and a curable resin which is compatible with the polymer and curable through a different curing reaction shows phase separation when cured, and can form cured products of various layered structure. Properties of a cured product obtained from the composition composed of a polymer having a hydrolyzable silyl group and epoxy resin compatible therewith greatly depend on cohesive force of the matrix. A method is proposed for incorporating a silane coupling agent which controls production of such cured product and for changing its content, as disclosed by Japanese Patent Laid-Open Publication No. 292616/1992.
The above-described curable composition can be controlled for the layered structure of the cured product. Therefore, the curable resin composition can be improved in modulus of elasticity and tensile shear strength, because size of the dispersed epoxy resin particles and matrix strength can be changed over a wide range. However, the resin composition is still insufficient in curing speed and resistance to weather.
Therefore, there are demands for a rubber composition high in adhesion and curing speed, and giving various types of cured products of high resistance to weather and other characteristics, e.g., a cured product of greatly varying layered structures, another cured product of low modulus of elasticity and high elongation, or still another cured product of high modulus of elasticity and tensile shear strength realized by decreasing size of the dispersed epoxy resin particles and increasing epoxy resin content of the matrix.
(14) A rubber-based organic polymer having a hydrolyzable silyl group, although showing an interesting characteristic that it can be cured even at room temperature into a rubber elastomer, normally has a disadvantage of insufficient strength of the cured product, which limits its applicable areas.
Japanese Patent Laid-Open Publication No. 280217/1987 discloses a curable composition composed of a rubber-based organic polymer having a hydrolyzable silyl group and epoxy resin, incorporated with two types of silicon compounds, one having both a functional group reactive with an epoxy group and hydrolyzable silicon group in the molecule, and the other having at least two hydroxyl groups bonded to a silicon atom in the molecule, in order to overcome the disadvantages of the conventional cured rubber-based organic polymer having a hydrolyzable silyl group.
Incorporation of these silicon compounds into the curable composition improves insufficient strength of the rubber-based organic polymer having a hydrolyzable silicon group, and gives the cured product of high strength irrespective of moisture quantity. The composition, however, still has disadvantages of insufficient curing speed and resistance of the cured product to weather.
Therefore, there are demands for a curable rubber composition improved in toughness and strength, giving the cured product of high strength irrespective of moisture quantity, and, at the same time, high in curing speed and giving the cured product of high resistance to weather.
(15) A saturated hydrocarbon-based polymer containing a reactive silicon group is crosslinked by hydrolysis of the reactive silicon group with moisture proceeding even at room temperature and subsequent formation of the siloxane bond, to give a rubber-like cured product. As such, it is used as sealant for laminated glass and elastic sealant for buildings.
The elastic sealant for buildings is generally incorporated with a filler of calcium carbonate, e.g., gelatinized calcium carbonate or limestone powder. The composition incorporated with gelatinized calcium carbonate for sealants is high in thixotropy, has less thready, and hence is high in workability. The cured product is suitable for sealants for buildings, because of its tensile-related properties of low modulus and high elongation.
Limestone powder, on the other hand, is used as a bulking agent.
A sealant for laminated glass is required to have a sufficiently high modulus and strength to support the glass, unlike a sealant for buildings which is required to have a low modulus and high elongation. It is therefore essential for a sealant for laminated glass to have mechanical properties, e.g., strength and hardness, and, at the same time, good workability. However, a composition containing a saturated hydrocarbon-based polymer having a reactive silicon group cannot simultaneously satisfy these properties.
Japanese Patent Laid-Open Publication No. 316804/1998 discloses a saturated hydrocarbon-based polymer having a reactive silicon group incorporated with calcium carbonate and talc as the curable composition that can solve the problem of inclusively satisfying these properties. However, the proposed composition may not always sufficiently satisfy workability and mechanical properties. Moreover, it is not always satisfactory in curing speed and resistance to weather of the cured product.
Therefore, there are demands for a rubber composition well-balanced between workability and mechanical properties of the cured product, sufficient in curing speed and resistance to weather of the cured product, and suitable as a sealant for laminated glass.
(16) A curable polymer is a liquid or the like moldable before curing, giving a solid, e.g., rubber-like one, of high strength when cured. The curable polymer is widely used for adhesives and sealants. The adhesives and sealants for glass and plastics are required to have an additional property of resistance to light, because the surface for which they are used is irradiated with light, unlike the ones which are used for opaque materials. They completely lose the function of adhesive or sealant, when deteriorated with light, because the adhesive layer will peel off. Adhesion is specifically referred to as weather-resistant adhesion, when it is required to have resistance to light as an important property for transparent materials. An adhesive or sealant for buildings, in particular, is required to retain the additional property of weather-resistant adhesion for extended periods. The adhesion layer is very thin and will lose weather-resistant adhesion, when it is made of a material insufficient in resistance to weather to any extent. There are not many materials which show excellent weather-resistant adhesion.
A saturated hydrocarbon-based polymer having a crosslinkable silicon group falling into the category of curable polymers is cured, e.g., by the actions of moisture in air. When cured, it will show favorable characteristics, e.g., high resistance to weather and heat, adhesion in the presence of water, non-polluting nature, and low moisture permeability. Moreover, it shows good workability and is sprayed smoothly, because it can be fluid to have an adequate viscosity and structural viscosity (thixotropy) at room temperature. In addition, the polymer is not malodorous, giving off little odor while being handled, and particularly suitable for sealants (Japanese Patent Laid-Open Publication No. 6041/1988). Japanese Patent Laid-Open Publication No. 198673/1989 describes that the above polymer can be used as a sealant also for transparent material, e.g., laminated glass. When used for laminated glass, it brings about the merits of increasing line production speed and showing its effect by single sealing, instead of double sealing required for the conventional one, because it can be quickly cured under heating. It can be also used for laminated glass double-sealed by the common method, needless to say.
It is found, however, when a curable composition containing a saturated hydrocarbon-based polymer having a crosslinkable silicon group is used for some transparent materials, in particular surface-treated glass such as heat ray reflective type, the cured composition may not always show sufficient weather-resistant adhesion.
Japanese Patent Laid-Open Publication No.286895/1997 proposes a curable composition containing a saturated hydrocarbon-based polymer having a crosslinkable silicon group incorporated with a combination of specific light stabilizer and silane coupling agent, as the one with improved weather-resistant adhesion for surface-treated glass. However, its cured product is still insufficient in resistance to weather, and there is room for improvement in its curing speed.
Therefore, there are demands for a curable composition high in curing speed, giving its cured product of high resistance to weather, and suitable for adhesives and sealants.
(17) A polyalkylene oxide-based polymer, e.g., polypropylene oxide-based polymer, having a reactive silicon group at the terminal of the molecule is already known. It has a characteristic of being cured with moisture even at room temperature into a rubber-like solid. However, the polymer has disadvantages of insufficient resistance to heat, water and weather.
Therefore, there are demands for a curable rubber composition containing, as the main ingredient, a silyl-containing rubber containing a specific hydrolyzable silyl group in the molecule, and giving the cured product excellent in resistance to weather and heat.
(18) A saturated hydrocarbon-based polymer having at least one reactive silicon-containing group, with hydroxyl or a hydrolyzable group bonded to the silicon atom and crosslinkable by forming the siloxane bond, is known to show interesting nature that it is crosslinked with moisture or the like even at room temperature by forming the siloxane bond accompanied with the hydrolysis or the like of the reactive silicon group, to form a rubber-like cured product. Therefore, it is useful for, e.g., sealants for laminated glass and elastic sealants for buildings.
A sealant for laminated glass is required to have non-primer adhesion, i.e., to be fast adhesive to various objects in the absence of a primer. More recently, the above property has been required not only for sealant for laminated glass but also for sealant for other purposes, e.g., by elastic sealant for buildings, to improve application efficiency by dispensing with a primer. However, the sealant which uses the above-described saturated hydrocarbon-based polymer containing a reactive silicon group is insufficient in adhesion in the absence of a primer.
Moreover, a sealant for laminated glass, in particular that for the glass fringe, is required to be excellent especially in weather-resistant adhesion. The above-described saturated hydrocarbon-based polymer containing a reactive silicon group is somehow insufficient in weather-resistant adhesion. In particular, it has a disadvantage of insufficient weather-resistant adhesion for highly insulating, heat ray reflective glass, which has been widely used recently.
Japanese Patent Laid-Open Publication No.152584/1998 discloses a curable composition comprising (A) a saturated hydrocarbon-based polymer containing at least one reactive silicon group, (B) a silane coupling agent, and (C) a compound containing an unsaturated group in the molecule which triggers polymerization by reacting with oxygen in air, and/or photopolymerizable compound. However, this curable composition has still room for improvement both in curing speed and resistance to weather.
Therefore, there are demands for a curable composition containing, as the main ingredient, a saturated hydrocarbon-based polymer having a reactive silicon group which is highly adhesive to various materials, improved in weather-resistant adhesion for various types of glass, in particular heat ray reflective glass, and excellent in resistance to weather and curing speed.
(19) A silicone-based tack agent of silicone resin based on dimethyl polysiloxane rubber is known as a heat-resistant tack agent.
However, it is generally known that this silicone-based tack agent has disadvantages, e.g., strong tackiness with non-polar compounds, e.g., polytetrafluoroethylene, and compatibility with the so-called silicone releasing paper coated with a silicone releasing agent, because both contain polysiloxane, making itself difficult to peel off the releasing paper and damaging its releasing effect.
On the other hand, tack agents of good releasing property include those composed of a component having only an organic skeleton, e.g., rubber-based tack agents, such as natural or synthetic rubber incorporated with a tackifier resin, and acrylic-based tack agents produced by copolymerization with an acrylate ester. They have their own disadvantages; for example, the former is of non-crosslinking type and cannot be expected to have high resistance to heat, while the latter, although crosslinkable by the actions of a crosslinking agent, e.g., that of isocyanate, incorporated therein, may not give the crosslinked product itself showing sufficient resistance to heat. Therefore, they may not show sufficient resistance to heat as a tack agent.
Recently, use of a group containing hydrolyzable silicon is proposed to obtain a tack agent of high resistance to heat, wherein the group triggers a condensation reaction in the polymer of organic skeleton in which it is incorporated, to form the thermally stable siloxane crosslinking.
Such a tack agent composition is disclosed by, e.g., Japanese Patent Laid-Open Publication No.71377/1984. This siloxane-crosslinking type tack agent has a disadvantage of poor relesability, as is the case with the above-described silicone-based tack agent, in spite of its polymer main chain being essentially of organic skeleton. More concretely, when it is adhered to a releasing paper or film coated with a silicone-based releasing agent, or when a laminate with the tack agent on one side of the base and silicone-based releasing agent on the other side is wound, exfoliation resistance between the tack agent and releasing paper or releasing film increases with time, possibly breaking the releasing paper when the worst comes to the worst, and making it impossible to release the paper.
As is generally known, a silicone-based releasing paper frequently serves as the essential component of adhesive tapes, and the so-called silicone-based tack agent described above is not well separated from a silicone-based releasing paper. Although development of releasing paper coated with a non-silicone-based (e.g., fluorine-based) releasing agent has been considered, application of the tack agent to releasing paper is limited, because it is not smoothly separated from the paper.
Japanese Patent Laid-Open Publication No.60771/1986 discloses a tack agent composition comprising (A) an organic polymer containing at least one hydrolyzable silicon group in the molecule, (B) a tackifier resin, and (C) a specific organic zirconium or aluminum as the curing catalyst. It is developed in consideration of the actual situations that there is no tack agent composition high in resistance to heat and well releasable from a releasing paper coated with a silicone-based releasing agent. The composition is said to be well releasable from a silicone-based paper or film.
However, further improvements in releasability and resistance to heat have been desired. Moreover, improvements in resistance to weather and curing speed are left as the major technical problems to be solved.
Therefore, there are demands for a tack agent composition high in resistance to heat, well releasable from a releasing paper or the like coated with a silicone-based releasing agent, and also high in curing speed and resistance to weather.
(20) Japanese Patent Laid-Open Publication No.36395/1979 describes that a vinyl-based resin containing a hydrolyzable silyl group at the terminal or in the side chain is not only excellent in, e.g., gloss, resistance to weather and discoloration, but improved in adhesion to inorganic materials by the actions of the hydrolyzable silyl group, and forming a resin of dense network structures by crosslinking at room temperature with moisture, in particular that in air to have high hardness, and resistance to solvent, water, heat and weather.
According to Japanese Patent Laid-Open Publication No.63351/1982, however, the vinyl-based resin containing a hydrolyzable silyl group, although giving an excellent resin when cured in the presence of a curing catalyst, has a disadvantage of short pot life in the open atmosphere, in particular when the vinyl-based resin having 3 hydrolyzable silyl groups contains the curing catalyst.
The above publication also describes the followings.
The inventions to improve the pot life in open atmospheres have been already applied for patents. For example, U.S. Pat. No. 4,043,953 discloses an invention which improves pot life of a polymerized organic silane in the presence of a curing catalyst, wherein the polymer is produced by copolymerization of a monomer containing a CH2═C< group, except the one containing an active hydrogen group, e.g., hydroxyl, carboxyl and amide group, with acrylate alkoxysilane, methacrylate alkoxysilane or vinyl alkoxysilane, and incorporated with a hydrolyzable, reactive silane monomer represented by the general formula XnSi(OR)4-n (wherein, X is an organic group of 1 to 12 carbon atoms; R is methyl, ethyl, 2-methoxymethyl, 2-ethoxyethyl, or an alkyl group having a carbon number of 5 or less; and “n” is an integer of 0 to 2) at 0.5 to 15% by weight, based on the polymerized organic silane.
The curing catalysts useful for the above invention include an organic acid, e.g., p-toluene sulfonate and n-butyl phosphate; metallic salt of orgaic acid, e.g., tin naphthenate, dibutyl tin dilaurate, iron stearate and lead octenate; and organic amine, e.g., boron isodiamine, methylene diamine and imidazole at 0.1 to 5% by weight, preferably 0.2 to 1% by weight. However, the pot life was measured after the polymerized organic silane, hydrolyzable, reactive silane monomer and curing catalyst were stored in a closed condition in the embodiments. The publication is silent on pot life in an open atmosphere, which is of practical importance. Indeed, pot life of the polymerized organic silane, hydrolyzable, reactive silane monomer and curing catalyst, as described in the USP publication, in an open atmosphere is satisfactory only when an organic amine is used, and short in the other cases. However, the resin cured in the presence of an organic amine has a disadvantage of coloration by the amine, and development of other catalysts has been desired.
Japanese Patent Laid-Open Publication No.63351/1982 discloses a composition of improved pot life, developed under the above situations. The publication discloses a composition of improved pot life, comprising
100 parts by weight of a vinyl-based silyl group containing resin with the main chain essentially composed of a vinyl-based polymer and having at least one silicon group bonded to a hydrolyzable group in the molecule at the terminal or in the side chain, and
0.01 to 10 parts by weight of a curing catalyst selected from the group consisting of a mercaptide type organotin compound having the Sn—S bond, a sulfide type organotin compound having the Sn═S bond, a mixture of a carboxylate type organotin compound and a mercaptide type organotin compound having the Sn—S bond, a mixture of a carboxylate type organotin compound and a sulfide type organotin compound having the Sn═S bond, a mixture of a carboxylate type organotin compound and organic carboxylic acid, a mixture of a carboxylate type organotin compound and organic carboxylate anhydride, and a mixture of an organic carboxylate compound and organic carboxylate anhydride.
The above-described vinyl-based resin containing silyl group can be produced by reacting a hydrosilane compound with a vinyl-based resin having the C—C double bond in the presence of a catalyst of Group VIII transition metal. The publication describes that the vinyl-based resin useful for the invention is not limited, except that it contains a hydroxyl group, and that the adequate resins include (meth)acrylate ester, e.g., methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate; carboxylic acid, e.g., (meth)acrylic acid, itaconic acid and fumaric acid; acid anhydride, e.g., maleic anhydride; epoxy compound, e.g., glycidyl (meth)acrylate; amino compound, e.g., diethylaminoethyl acrylate and aminoethyl vinyl ether; amide compound, e.g., (meth)acrylamide, amide itaconate, α-ethylacrylamide, crotonamide, diamide fumarate, diamide maleate and N-butoxymethyl (meth)acrylamide; and resin containing, as the main ingredient, a copolymer selected from the group consisting of acrylonitrile, styrene, α-methyl styrene, vinyl chloride, vinyl acetate, vinyl propionate and the like.
Japanese Patent Laid-Open Publication No.63351/1982, however, is silent on ethylene/α-olefin/non-conjugated polyene random copolymer rubber produced by copolymerization of ethylene, α-olefin of 3 to 20 carbon atoms and norbornene compound having vinyl group (═C═CH2) at the terminal, instead of the vinyl-based resin.
Therefore, there are demands for a curable rubber composition composed of an ethylene/α-olefin/non-conjugated polyene random copolymer rubber containing a hydrolyzable silyl group at the terminal or in the side chain and curing catalyst, improved in pot life in an open atmosphere, high in curing speed, and excellent in resistance to weather.
(21) A curable composition containing an organotin compound is already known, where the organotin compound is in the form of a saturated hydrocarbon-based polymer having at least one silicon-containing group with hydroxyl or a hydrolyzable group bonded to the silicon atom and crosslinkable by forming the siloxane bond (such a silicon-contaiing group is hereinafter referred to as reactive silicon group). However, such curable composition involves various problems, e.g., low in curing speed, residual tackiness and insufficient curing of the thin film.
Japanese Patent Laid-Open Publication No.41360/1996 describes use of a specific organotin compound in order to solve the above problems. However, the composition has been strongly desired to have further improved curing speed. At the same time, improvement in resistance to weather has been left as the major problem to be solved.
Therefore, there are demands for a curable composition forming the three-dimensional network structures with moisture in air, quickly cured into the solid of rubber-like elasticity, and excellent resistance to weather.
(22) A saturated hydrocarbon-based polymer having at least one reactive silicon group in the molecule is known to have interesting nature that it is crosslinked with moisture or the like even at room temperature by forming the siloxane bond accompanied with the hydrolysis or the like of the reactive silicon group, to form a rubber-like cured product. The polymer is excellent in resistance to heat, water and weather, and useful for sealants for laminated glass and elastic sealants for buildings.
The sealant for laminated glass is required to have excellent non-primer adhesion,i.e., to be fast adhesive to various objects in the absence of a primer. More recently, the above property has been required not only for sealant for laminated glass but also for sealant for other purposes, e g., by elastic sealant for buildings, to improve application efficiency by dispensing with a primer. However, the sealant which uses the above-described saturated hydrocarbon-based polymer containing a reactive silicon group is insufficient in adhesion in the absence of a primer. Moreover, it is not always satisfactory in curing speed and resistance to weather.
Therefore, there are demands for a curable rubber composition containing, as the major ingredient, rubber containing a hydrolyzable silyl group, high in curing speed, and excellent in adhesion to various objects and in resistance to weather.
(23) The vehicle bodies have been coated with an underbody coating material on the back side of the floor or sides for various purposes, e.g., prevention of damages by gravel or the like bounded back on a running vehicle, rust prevention and damping to reduce vibration and noise, and also with a body sealer on a place structurally difficult to treat for rust prevention, e.g., joint between the internal and external plates, for prevention of rust by rainwater, moisture or the like. Vinyl chloride sol has been used as the material suitable for the above purposes.
Recently, the coating material for vehicles is strongly required to have better functions, e.g., still improved rust-prevention and damping effects by the thinner film for reducing weight, and reduced vehicle baking temperature or even dispensing with the baking step for resources- and energy-saving viewpoints.
Vinyl chloride sol, although inexpensive and meeting the minimum requirements, has a disadvantage that sufficient rust-preventive effect or resistance to chipping (or damage-preventive effect) may not be realized at low baking temperature, because of slow gelation. Moreover, its damping effect is inherently not very high, and tends to further deteriorate as the coating film is required to be thinner.
Japanese Patent Laid-Open Publication No.41349/1996 discloses a coating material for vehicles comprising a saturated hydrocarbon-based polymer having a reactive silicon group as the crosslinking group. It is improved in various properties, e.g., those related to low-temperature baking, rust prevention, resistance to chipping and damping as compared with vinyl chloride sol. Nevertheless, however, these properties are still insufficient, in particular damping property being expected for further improvement. Improvements are also expected for curing speed and weather resistance of the coating film thereof.
Therefore, there are demands for a curable composition, e.g., coating material for vehicles, high in curing speed even at low baking temperature, fast curable, and forming the uniform, stable coating film even when it is thin, excellent in rust prevention, chipping resistance, damping properties and weather resistance.
(24) Many industries, e.g., building, automobile and electric appliance industries, have been using a variety of sealants for joining similar or dissimilar materials in assembling/fabrication lines, and also for other purposes, e.g., reinforcement, repair and replacement. Sealants of various curing modes or main chain structures have been proposed for specific purposes. However, few sealants commonly used for laminated glass satisfy all of resistance to weather and heat, non-polluting property, low moisture-permeability and weather-resistant adhesion. Still less is the sealant having low-odor property, in addition to the above.
For example, a polysulfide-based sealant now being used is insufficient in low moisture-permeability, although showing excellent weather resistance, heat resistance and non-polluting properties, and cannot be used for single sealing independently.
It is also insufficient in weather-resistant adhesion, one of the most important properties for sealing laminated glass, for heat ray reflective glass, which has been recently massively used for energy-saving purposes. In laminated glass production, this may need an additional step of removing a metallic coating film that reflects heat ray before the glass is filled with the sealant. Moreover, it is also insufficient in properties related to hot water-resistant adhesion and low odor, leaving environmental problems in the laminated glass production process.
A condensing curing type silicone-based sealant, as another type of sealant for laminated glass, is insufficient in non-polluting property and low moisture-permeability, although satisfying weather resistance, heat resistance, weather-resistant adhesion and low-odor properties, and cannot be used for single sealing independently.
Therefore, there are demands for a sealant for laminated glass satisfying weather resistance, heat resistance, non-polluting, low moisture-permeability, weather-resistant adhesion and low-odor properties, and also excellent in mechanical characteristics and producible at low cost.
(25) Sealants for laminated glass fall into two general categories, for primary and secondary sealing. A laminated glass unit is sealed at its edges with one type of sealant (single sealing) or 2 types of sealants for primary and secondary sealing (dual sealing), depending on specific purposes.
A butyl rubber-based hot melt resin (hereinafter sometimes referred to as hot melt butyl) is commonly used as a sealant for single sealing and primary sealant for dual sealing. It has following characteristics.
Hot melt butyl is a solid or waxy polymer at room temperature, becoming fluid when heated at around 100 to 250° C. When used as an adhesive, it is adhered to various base surfaces after being molten by wetting these surfaces. In an actual laminated glass production process, hot melt butyl is discharged from a dedicated applicator by which it is molten under heating, and solidified after it is applied as sealant temperature rapidly decreases. Therefore, it is curable for a much shorter period than other reaction-curing type sealants, and hence can greatly reduce the curing period and facilitate sealant management and handling. Therefore, it will play a still more important role in the future laminated glass markets, because of its good workability to simultaneously realize its reduced procurement periods and increased productivity.
However, single-sealed laminated glass, mainly using hot melt butyl, is low in structural strength and difficult to secure steam-barrier property at the laminated glass inside for extended periods. Therefore, it can find limited industrial applications, e.g., sealant for show case units, which are replaced in a relatively short cycle.
The secondary seal in a dual-sealed laminated glass is low in steam-barrier property, although high in mechanical characteristics (e.g., adhesion to the glass), and needs primary sealing. Therefore, it is structured to block steam passing through the secondary seal by hot melt butyl. This dual-sealed laminated glass needs 2 types of sealants in the production process, and is more costly, although having longer serviceability, than the single-sealed type. Even a dual-sealed laminated glass cannot sustain primary sealing, when the secondary seal is aged, possibly deteriorated to the single-sealed glass grade.
Adhesion of hot melt butyl depends on tackiness of butyl rubber, and is possibly deteriorated by embrittlement at low temperature. Moreover, the sealant is thermoplastic at high temperature, possibly its softening to cause deviation of the laminate components from each other, andhence is required to be resistant to creeping at high temperature to prevent the above problems.
Comparing thermoplastic hot melt butyl with the reaction-curing type sealant (e.g., polysulflde-based or silicone-based sealant), the former has at present major disadvantages of significant fluctuations of properties, e.g., mechanical properties, with temperature, although much better in workability. Therefore, it tends to have narrower applicable areas in terms of glass size and weight than the reaction-curing type.
Therefore, there are demands for a sealant for laminated glass, improved in temperature-dependence of structural strength and adhesion to a base material, while keeping steam-barrier characteristics of hot melt butyl, and suitable as the sealant for laminated glass for primary sealing for dual sealing or single sealing.
The present invention has the following objects.
(1) The present invention is intended to solve the problems involved in the conventional technologies (1) described above. Accordingly, it is an object of the present invention to provide a curable elastic composition (curable rubber composition) improved in elongation of the cured product and residual tackiness, in its surface and, at the same time, high in curing speed and capable of giving the cured product of high resistance to weather, and also to provide use of the same.
(2) The present invention is also intended to solve the problems involved in the conventional technologies (2) described above. Accordingly, it is another object of the present invention to provide a curable rubber composition containing, as the main ingredient, a silyl-containing ethylene/α-olefin/non-conjugated polyene random copolymer rubber which has a structural unit derived from a norbornene compound as the non-conjugated polyene with a specific vinyl group at the terminal and containing a specific hydrolyzable silyl group in the molecule, and high in curable speed and excellent in adhesion to a variety of objects and resistance to weather, and also to provide use of the same.
(3) The present invention is also intended to solve the problems involved in the conventional technologies (3) described above. Accordingly, it is still another object of the present invention to provide a curable composition high in curing speed, leaving little residual tackiness on the cured product surface, after it is cured, highly resistant to weather, showing high adhesion between a paint and sealant surface, when the former is applied, and useful for sealant, primer or the like.
(4) The present invention is also intended to solve the problems involved in the conventional technologies (4) described above. Accordingly, it is still another object of the present invention to provide a curable composition containing a rubber-based organic polymer having a reactive silicon group, which is rapidly cured with moisture, excellent in tensile-related properties, capable of giving a rubber-like elastomer free of residual tackiness on the surface, and improved in resistance to weather and storage stability.
(5) The present invention is also intended to solve the problems involved in the conventional technologies (5) described above. Accordingly, it is still another object of the present invention to provide a rubber composition curable at room temperature, high in curing speed, excellent in resistance to weather, and capable of giving the highly adhesive cured product, and also to provide use of the same.
(6) The present invention is also intended to solve the problems involved in the conventional technologies (6) described above. Accordingly, it is still another object of the present invention to provide a curable rubber composition, easily cured with moisture in air at room temperature or under heating, and at high speed, and excellent in resistance to weather.
(7) The present invention is also intended to solve the problems involved in the conventional technologies (7) described above. Accordingly, it is still another object of the present invention to provide a curable composition high in curing speed, giving a weather-resistant cured product, and suitable for adhesive, sealant or the like.
(8) The present invention is also intended to solve the problems involved in the conventional technologies (8) described above. Accordingly, it is still another object of the present invention to provide a curable composition quickly cured when it is used, even after being stored for extended periods, and giving a weather-resistant cured product.
(9) The present invention is also intended to solve the problems involved inthe conventional technologies (9) described above. Accordingly, it is still another object of the present invention to provide a curable rubber composition high in storage stability and curing speed, and giving a highly weather-resistant cured product, and also to provide use of the same.
(10) The present invention is also intended to solve the problems involved in the conventional technologies (10) described above. Accordingly, it is still another object of the present invention to provide a new curable rubber composition which incorporates a hydrate of metallic salt as the moisture source, and also to provide use of the same.
It is still another object of the present invention to provide a curable rubber composition showing no increase in viscosity while being stored, high in curing speed and resistance to weather, and also to provide use of the same.
It is still another object of the present invention to provide a curable rubber composition which can incorporate a compound having a reactive silicon group readily reactive with moisture, e.g., silane coupling agent, and also to provide use of the same.
(11) The present invention is also intended to solve the problems involved in the conventional technologies (11) described above. Accordingly, it is still another object of the present invention to provide a composition low in viscosity, good in workability, sufficient in curing speed, excellent in, e.g., resistance to weather, heat and water, and capable of giving a rubber-like cured product high in strength and elongation (low modulus of elasticity).
(12) The present invention is also intended to solve the problems involved in the conventional technologies (12) described above. Accordingly, it is still another object of the present invention to provide a rubber composition high in vulcanization speed, improved in resistance to weather and excellent in mechanical strength, while retaining the various favorable characteristics of an ethylene/α-olefin/non-conjugated polyene random copolymer rubber, e.g., excellent resistance to heat and chemicals of the vulcanized product.
(13) The present invention is also intended to solve the problems involved in the conventional technologies (13) described above. Accordingly, it is still another object of the present invention to provide a rubber composition high in adhesion; giving the cured product with greatly changed layered structures, low in elasticity and high in elongation; giving the cured product dispersed with an epoxy resin whose content in the matrix increases as its particle size decreases, and high in modulus of elasticity and tensile shear strength; sufficiently high in curing speed, and giving the cured product of high resistance to weather, and also to provide a method of producing the same.
(14) The present invention is also intended to solve the problems involved in the conventional technologies (14) described above. Accordingly, it is still another object of the present invention to provide a curable rubber composition improved in toughness and strength, giving the cured product of high strength irrespective of moisture quantity, and, at the same time, high in curing speed and giving the cured product of high resistance to weather.
(15) The present invention is also intended to solve the problems involved in the conventional technologies (15) described above. Accordingly, it is still another object of the present invention to provide a rubber composition well-balanced between workability and mechanical properties of the cured product, sufficient in curing speed and resistance to weather of the cured product, and suitable as a sealant for laminated glass.
(16) The present invention is also intended to solve the problems involved in the conventional technologies (16) described above. Accordingly, it is still another object of the present invention to provide a curable composition high in curing speed, giving the cured product of high resistance to weather, and suitable for adhesives and sealants.
(17) The present invention is also intended to solve the problems involved in the conventional technologies (17) described above. Accordingly, it is another object of the present invention to provide a curable rubber composition containing, as the main ingredient, a silyl-containing ethylene/α-olefin/non-conjugated polyene random copolymer rubber which has a structural unit derived from a norbornene compound with a specific vinyl group at the terminal as the non-conjugated polyene and containing a hydrolyzable silyl group in the molecule, and giving the cured product excellent in resistance to weather and heat, and also to provide use of the same.
(18) The present invention is also intended to solve the problems involved in the conventional technologies (18) described above. Accordingly, it is still another object of the present invention to provide a curable rubber composition containing, as the main ingredient, a saturated hydrocarbon-based polymer having a reactive silicon group, which is highly adhesive to various materials, improved in weather-resistant adhesion for various types of glass, in particular heat ray reflective glass, and excellent in resistance to weather and curing speed.
(19) The present invention is also intended to solve the problems involved in the conventional technologies (19) described above. Accordingly, it is still another object of the present invention to provide a tack agent composition high in resistance to heat, well releasable from a releasing paper or the like coated with a silicone-based releasing agent, and also high in curing speed and resistance to weather, and also to provide use of the same.
(20) The present invention is also intended to solve the problems involved in the conventional technologies (20) described above. Accordingly, it is still another object of the present invention to provide a rubber composition composed of an ethylene/α-olefin/non-conjugated polyene random copolymer rubber containing a hydrolyzable silyl group at the terminal or in the side chain and a curing catalyst, improved in pot life in an open atmosphere.
It is still another object of the present invention to provide a curable rubber composition high in curing speed and excellent in resistance to weather, and also to provide use of the same.
(21) The present invention is also intended to solve the problems involved in the conventional technologies (21) described above. Accordingly, it is still another object of the present invention to provide a new curable composition forming the three-dimensional network structures with moisture in air, quickly cured into the solid of rubber-like elasticity, and excellent resistance to weather.
(22) The present invention is also intended to solve the problems involved in the conventional technologies (22) described above. Accordingly, it is still another object of the present invention to provide a curable rubber composition containing, as the major ingredient, an ethylene/α-olefin/non-conjugated polyene random copolymer rubber containing a hydrolyzable silyl group, high in curing speed, and excellent in adhesion to various objects and in resistance to weather.
(23) The present invention is also intended to solve the problems involved in the conventional technologies (23) described above. Accordingly, it is still another object of the present invention to provide a curable composition, e.g., coating material for vehicles, high in curing speed even at low baking temperature, fast curable, and forming the uniform, stable coating film even when it is thin, excellent in rust prevention, chipping resistance, damping properties and resistance to weather.
(24) The present invention is also intended to solve the problems involved in the conventional technologies (24) described above. Accordingly, it is still another object of the present invention to provide a sealant for laminated glass satisfying weather resistance, heat resistance, non-polluting, low moisture-permeability, weather-resistant adhesion and low-odor properties, and also excellent in mechanical characteristics and producible at low cost.
(25) The present invention is also intended to solve the problems involved in the conventional technologies (25) described above. Accordingly, it is still another object of the present invention to provide a sealant for laminated glass, improved in temperature-dependence of structural strength and adhesion to a base material, while keeping steam-barrier characteristics of hot melt butyl, and suitable as the sealant for laminated glass for primary sealing for dual sealing or single sealing.